This invention provides novel shock-absorbing methods and apparatus making use of shape memory alloys (SMAs) and novel shock-absorbing components for use in those other methods and apparatus. As further explained below, SMAs can absorb shock in finite amounts, typically up to about 7%, by a change in the crystal structure of the alloy. Superelastic SMAs will recover to (or towards) an original shape spontaneously upon removal of the deforming forces. Martensitic SMAs can be recovered to (or towards) an original shape by reversal of the deforming forces or by heating to a transformation temperature.
Many different apparatus for absorbing shocks are known. Some shock-absorbing apparatus, often referred to as damping apparatus, will absorb repetitive shocks. Shock-absorbing devices comprising a shape memory alloy (SMA) have been proposed. However, the known devices containing SMAs have one or more disadvantages. For information about shape memory alloys, which are well-known to those skilled in the art, and the use of particular SMAs in particular shock-absorbing apparatus, reference may be made for example to U.S. Pat. No. 5,398,916; U.S. Pat. No. 5,842,312; U.S. Pat. No. 6,796,408; U.S. Pat. No. 7,398,964; US 2009/002-5833; WO 2007/039271; Auricchio et al, J. Earthquake Engineering, 10, 1 (2006), 1-22; Duerig et al, Engineering Aspects of Shape Memory Alloys, 1990; Liu et al., Proc, Final Workshop of Brite-Euram Manside Project, II 59-18; Tyber et al., J. Eng, Mechanics, ASCE, September 2007, 1009-1029; Desroches et al, J, Earthquake Engineering, 8, 415-429; Krumme et al. Proceedings of SPIE, San Diego, Calif., USA, v. 2445, pp 225-240; and Cardone et al, Proc, Final Workshop of Brite-Euram Manside Project, II 5-103. The entire disclosure of each of those patents and references is incorporated herein by reference for all purposes.